The Night Elf heritage armor questline is now available on live servers in Patch 10.1.7, so we've played through to find out what happens and earn the Kaldorei Protector's Adornment and extra rewards!
The questline starts with The Clarion Call, which is a message from Arko'narin Starshade, summoning the player to the Stormwind Embassy, as Maiev has requested for us, as Tyrande has called the Wardens to action in Felwood.
In Ancient Curses we learn that the call is about a resurgence of demonic corruption in Felwood. Tyrande sent a contingent of Sentinels to investigate, but none of them returned, so she asked for Maiev's help, which asked for the player's assistance personally.
There we also meet Maiev's assistance during this mission, the siblings Arko'narin Starshade and Lysander Starshade. At first glance, we already have questions about Arko'narin, noting that she has a Sword for a weapon, instead of a Glaive like other Wardens. When we ask her about it, she tells us that the sword is a memento.
After accepting the quest, we listen to the siblings talking about the mission.